1. Field of the Invention
This invention relates to hydraulic fluids for use in machinery and other mechanical systems, and is especially directed to hydraulic fluids for use in machinery that is used in outdoor environments where the unintentional dispersal of hydraulic fluid from such machinery will not harm the surrounding vegetation or the environment.
2. Description of Related Art
It has been a particular problem that machinery used for various outdoor purposes has a tendency to leak hydraulic fluid into the surrounding environment. Conventional petroleum-based hydraulic fluids are well known to have deleterious effects on the environment, such as killing vegetation and polluting the ground and ground water.
Of particular concern in this regard is machinery used to groom golf courses or commercial garden areas, and equipment or machinery used in or near environmentally sensitive areas (e.g., boats, ships, bridges, etc.). When conventional hydraulic fluid from motors, mowers, earth movers and other equipment leaks from the machinery onto the grass or garden areas, or into aquatic environments, the hydraulic fluid contaminates the vegetation and cannot be washed off. The vegetation dies within a short period of time thereafter, and re-seeding or re-planting cannot take place for several weeks to months after contamination. In the interim, the areas where the vegetation died off are unsightly.
In recognition of this problem, other fluid materials have been used as a replacement for conventional petroleum-based hydraulic fluids. For example, vegetable or plant-based oils (i.e., non-petroleum-based oils) have been used in machinery. However, such oils are either unsuitable for use as hydraulic fluids due to the demands of the machinery, and/or such substitute fluids still prove to be damaging to the vegetation because they cannot be easily washed off. Many non-petroleum oils have similar physical properties to petroleum-based products. For example, both have limited solubility in water, both create slicks on water and both form emulsions and sludges. Additionally, non-petroleum oils tend to be persistent and remain in the environment for long periods of time. Thus, non-petroleum or vegetable-based oils are not necessarily compatible with the environment.
Therefore, it would be advantageous to provide a fluid material that is highly suitable for use as hydraulic fluid in machinery that is used in environmentally-sensitive areas such that if the fluid leaks from the machinery, the fluid will be environmentally compatible (i.e., non-destructive to vegetation) and not contaminate and/or kill the vegetation.